This study adopted a descriptive cross-sectional design and was conducted between November 2024 and March 2025. This study aimed to determine the prevalence and antibiotic susceptibility patterns of asymptomatic bacteriuria (ASB) among individuals residing in public housing compounds in the Obinze, Owerri West Local Government Area of Imo State, Nigeria. A cross-sectional approach was chosen to provide a snapshot of the microbial and behavioral characteristics related to ASB within the study population at a single point in time. A total of 150 participants were selected using simple random sampling. Data were collected using structured questionnaires.

This study was conducted in Obinze, a semi-urban community located in the Owerri West Local Government Area of Imo State, southeastern Nigeria. Geographically, the community lies along the Owerri–Port Harcourt Expressway, approximately 3.5 kilometers from Avu, and is positioned at latitude 5°25′N and longitude 6°50′E, with an elevation of 61 meters above sea level. Obinze consists of several villages and shares borders with surrounding communities, such as Oforola, Avu, Ihiagwa, Eziobodo, Umuokanne, Nekede, and Mbirichi. The area hosts key institutions, including the 34 Artillery Brigade Nigerian Army Base and the Federal University of Technology Owerri (FUTO), which contribute to its growing urban influence. Residential patterns vary across communities, with some households relying on shared sanitation facilities and others occupying self-contained housing units. The predominant economic activities include subsistence farming and petty trading, which reflect the community’s semi-urban character and socioeconomic diversity. These environmental and demographic characteristics particularly inconsistent access to sanitation and varied living conditions make Obinze a suitable setting for studying the prevalence of asymptomatic bacteriuria and its associated risk factors within a population at potential risk of undiagnosed urinary tract colonization.

A comprehensive range of materials and equipment were employed during the experimental procedures to facilitate the accurate collection, handling, and microbiological analysis of urine samples. Urine specimens were obtained from individuals residing in public housing using sterile wide-mouth urine containers (Sterilin™, Thermo Fisher Scientific, Cat. No. 128A) to ensure aseptic sample collection. Each container was labeled using markers, masking tape, and adhesive stickers for proper sample identification and traceability. Standard laboratory equipment included conical flasks, beakers, syringes (5 ml, BD Plastipak™, Cat. No. 300185), test tubes (Borosil ^®, Cat. No. 9820U06), test tube racks, Petri dishes (90 mm, Greiner Bio-One, Cat. No. 633102), and inoculating wire loops. Disposable nitrile gloves were consistently used to maintain sterility and protect personnel. Microbiological analyses were conducted using cysteine lactose electrolyte-deficient (CLED) (Oxoid™, Thermo Fisher Scientific, Cat. No. CM301) agar to isolate and differentiate urinary tract pathogens. The core analytical instruments included a compound light microscope (Olympus CX23), for microbial observation, an incubator (Memmert IN30, 37°C), to support controlled bacterial growth, a centrifuge (Hettich Rotina 420R), for sediment separation, and an autoclave (All American 25X, 121°C, 15 psi) for sterilization of reusable materials and media. Distilled water (Milli-Q ^®, Merck Millipore) was used for the preparation of reagents and for cleaning purposes. All the materials and equipment were thoroughly cleaned, sterilized, and appropriately preserved to ensure the validity and reliability of the experimental outcomes.

The representative sample consisted of 150 urine specimens. These samples were carefully collected randomly from households that lived in public compounds in Obinze. The number of samples collected was determined using Cochran’s formula for prevalence, and experimental and epidemiological studies. The nearest estimated proportion used for this study was that used by ( Elo-Ilo et al., 2013) in carrying out the prevalence of asymptomatic bacteriuria among preschool children in Nnewi in South-East Nigeria.

Each urine specimen (10–20 ml) was transferred into labeled test tubes and centrifuged at 2000 rpm for 15 min using a laboratory centrifuge. Following centrifugation, the supernatant was carefully decanted and discarded, and the sediment (pellet) was retained for microscopic examination and bacteriological analysis.

The cysteine lactose electrolyte-deficient medium (Oxoid™, CM301, 36 g/L) was prepared according to the manufacturer’s specifications and according to the method used by ( Bale et al., 2023). The agar medium was autoclaved at 121 ^oC°C for 15 min at 15 psi and then allowed to cool. About 15-20 ml of the prepared molten agar was dispensed into disposable petri dishes when the temperature was reduced to approximately 45 ^oC°C. They were allowed to set and ready for inoculation.

A total of (150) urine samples were examined using standard methods. First, the urine samples were serially diluted. From a suitable dilution factor (10 ⁻⁵), a sterile wire loop was used to carefully collect about 0.01 ml of the pellets of the urine sample and was used to inoculate the cysteine-lactose electrolyte deficient (CLED) using streaking method ( Bashir et al., 2016). The culture plates were incubated under aerobic conditions at 37°C for 24 h. Plates without visible growth were further incubated for an additional 24 h before they were discarded. The number and types of colonies grown in the media were recorded as insignificant when the samples had a colony count of less than 10 ⁴ CFU/ml. Samples with a colony count equal to or greater than approximately 10 ⁵ CFU ml of urine samples were considered to have significant bacteriuria. The bacterial isolates were identified based on a combination of cultural, morphological, and biochemical characteristics. The physiological characteristics of the colonies and their numbers on the culture plates were used as the basis for counting, taking into consideration their dilution number. Counts were made from plates containing 30-300 colonies which were according to the standard ( Bashir et al., 2016). Isolated microorganisms were subjected to Gram staining and biochemical tests to confirm them.

Urinalysis with Combi 9 stripe: After processing the urine samples, the combination of 9 stripes (Roche Diagnostics, Cat. No. 11894489216) was inserted aseptically into the urine samples, which were then observed and compared to the standard to determine the normality or abnormality of the following parameters: glucose, ketones, protein, blood, nitrite, pH, ascorbic acid, urobilinogen, and bilirubin.

Gram-staining was used to differentiate bacterial isolates into gram-positive and gram-negative bacteria. For the Gram staining process, clean slides were taken. A well-sterilized wire loop was used to make a smear on the slides, which were air-dried and fixed using heat. Crystal violet was poured on the slide, incubated for 1 min, and washed thoroughly with tap water. Gram iodine was used to flood the smear, allowed to stand for 1 min, and rinsed with tap water before re-flooding with 95% alcohol. The slides were allowed to stand for 15–20 s and then washed with tap water. Then, the secondary dye, safranin, was applied to the smear, allowed to stand for 1 min, and then rinsed with water. The slides were allowed to stand in normal air and then examined under a microscope with oil immersion at ×100 magnification. Staining enabled the differentiation of the bacteria into gram-positive and gram-negative bacteria. The procedure was performed according to the method described by Chessbrough et al. ( Carrillo et al., 2015).

Biochemical tests few biochemical tests were performed to confirm the microorganisms isolated from the urine samples. a.

Indole test: This was performed using Kovac’s reagent (Sigma-Aldrich, Cat. No. K2252) as adopted by ( Carrillo et al., 2015). The test was conducted over a 24-hour period. Bacterial isolates were first cultured in peptone water, after which 0.5 ml of Kovac’s reagent was added. The mixture was gently shaken and observed after one minute for the development of a red color, which indicated a positive reaction. Escherichia coli (ATCC 25922) was used as the positive control.

The number of isolated bacteria was counted based on the number of urine samples processed and the frequencies were recorded. The percentage of bacterial isolates was evaluated accordingly.

The data were analyzed using IBM SPSS Statistics version 28. Descriptive statistics, including frequencies and percentages, were used to summarize sociodemographic characteristics, ASB awareness, hygiene practices, and bacterial isolate distribution. Categorical variables were coded and entered in the SPSS database to ensure data integrity. Laboratory results from the culture and biochemical tests were analyzed to determine the frequency of each isolate. Data are presented using tables and charts to enhance the clarity and interpretation of the key findings.

Ethical approval for this study was obtained from the Ethics Committee of the Department of Science Laboratory Technology, Federal University of Technology Owerri (FUTO), Nigeria. The committee reviewed and approved the research protocol in accordance with institutional requirements for studies involving human participants. We clarify that the committee does not issue reference or approval numbers for departmental-level approvals; therefore, no formal number is available. All study procedures adhered strictly to the principles of the Declaration of Helsinki (2013 revision) on ethical conduct for research involving human participants. Prior to data collection, residents of the selected public compounds in Obinze were informed about the objectives, scope, and procedures of the study one week in advance. Verbal informed consent was obtained from all participants before the administration of questionnaires and urine sample collection, taking into account the low literacy level among some residents. Participants were assured of confidentiality, anonymity in reporting, and the voluntary nature of their participation, with the right to withdraw at any time without penalty. No minors were included in this study; therefore, parental consent and child assent were not applicable. Urine samples were collected using sterile universal containers, properly labeled with anonymized study codes, and transported in ice-cooled boxes to the Microbiology Laboratory, FUTO, within two hours of collection for analysis. All steps were conducted in accordance with biosafety and ethical standards, ensuring respect for participants’ autonomy, privacy, and safety.

All 150 screened participants met the diagnostic criteria for asymptomatic bacteriuria, defined as a urine culture yielding ≥10 colony-forming units (CFU)/mL in the absence of clinical symptoms. This represents a 100% prevalence rate, indicating a substantial and silent burden of ASB within the studied community. This finding reflects a likely underestimation of ASB in public health planning, and supports the need for targeted surveillance.

The sociodemographic characteristics of the respondents whose urine samples were used for bacteriuria examination are presented in Table 1. The age distribution ranged from 20 to 45 years, with the majority (62%) aged between 31 and 35 years, followed by 20% aged 26–30 years. The mean age was 32.8 ± 4.9 years. Females constituted a higher proportion (60%) than males (40%), reflecting the gender-based population dynamics in the study setting. Regarding educational attainment, 68% had no formal education, while only 4% had attained secondary or tertiary education, highlighting a low literacy level. Most of the participants were married (80%) and practiced Christianity (90%). Household sizes were relatively small in most cases, with 42% reporting 1–3 members and 40% reporting 4–6 members. These sociodemographic factors may influence hygiene behaviors and risk perceptions of tract infections.

This result represents the distribution of participants based on their awareness of bacteriuria, personal hygiene behaviors, and related health practices, as presented in Table 2. The responses reflected limited knowledge of asymptomatic bacteriuria, moderate understanding of personal hygiene, and generally positive practices in preventing infection transmission.

Almost all participants’ urine test results were markedly normal, as shown in Table 3. Normal urine should be yellow light to deep amber in color, free of blood, proteins, ketones, nitrites, glucose, bilirubin, and urobilirubin, with a pH between 4.5-8.

Biochemical and Gram staining characteristics were used to differentiate the five major bacterial isolates from urine samples, as presented in Table 4. Escherichia coli was identified by positive indole and catalase tests and negative citrate, urease, and Gram staining. Klebsiella spp. were positive for catalase, citrate, and urease, but negative for indole, coagulase, and gram-negative bacteria.

The total number of bacteria isolated from the urine samples collected from respondents in Obinze was seventy-five and presented in Table 5.

The distribution of bacterial isolates obtained from the urine samples of asymptomatic individuals is presented in Figure 1. Escherichia coli was the most prevalent organism, accounting for approximately 60% of the isolates, followed by Staphylococcus aureus (32%). Other bacteria detected included Enterococcus spp. (9%), Pseudomonas aeruginosa (10%), and Klebsiella spp. (5%). This distribution highlights the predominance of E. coli as the leading cause of asymptomatic bacteriuria while also demonstrating the presence of other clinically relevant uropathogens at lower frequencies. These findings underscore the microbial diversity among carriers despite the absence of overt urinary tract infection symptoms.

Based on the findings of this study, the following recommendations are proposed to effectively address asymptomatic bacteriuria (ASB) and its associated public health challenges in low-resource settings: 1.

Integrating ASB screening into primary healthcare services: Routine urine screening, especially for high-risk groups such as pregnant women, the elderly, and diabetics, should be included in community health outreach and antenatal care programs.